netdev - [PATCH v4 2/7] x86/tdx: Add TDREPORT TDX Module call support

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Message-Id: <20210806000946.2951441-3-sathyanarayanan.kuppuswamy@linux.intel.com>
Date:   Thu,  5 Aug 2021 17:09:40 -0700
From:   Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <mgross@...ux.intel.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>
Cc:     Peter H Anvin <hpa@...or.com>, Dave Hansen <dave.hansen@...el.com>,
        Tony Luck <tony.luck@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Kirill Shutemov <kirill.shutemov@...ux.intel.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Kuppuswamy Sathyanarayanan <knsathya@...nel.org>,
        x86@...nel.org, linux-kernel@...r.kernel.org,
        platform-driver-x86@...r.kernel.org, bpf@...r.kernel.org,
        netdev@...r.kernel.org
Subject: [PATCH v4 2/7] x86/tdx: Add TDREPORT TDX Module call support

The TDX Guest-Host Communication Interface (GHCI) includes a module
call (TDREPORT TDCALL) that a guest can make to acquire a copy of the
attestation data that it needs to verify its trustworthiness.

Add a wrapper function tdx_mcall_tdreport() that makes the module
call to get this data.

See GHCI section 2.4.5 "TDCALL [TDG.MR.REPORT] leaf" for additional
details.

[Xiaoyao: Proposed error code fix]
Reviewed-by: Tony Luck <tony.luck@...el.com>
Reviewed-by: Andi Kleen <ak@...ux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
---

Changes since v3
 * Rebased on top of Tom Lendacky's protected guest
   changes (https://lore.kernel.org/patchwork/cover/1468760/)

Changes since v2:
 * Included TDCALL_SUCCESS case check in tdx_mcall_tdreport().

 arch/x86/include/asm/tdx.h |  2 ++
 arch/x86/kernel/tdx.c      | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index 50693bd6f0dd..6e6abd2b0894 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -95,6 +95,8 @@ extern phys_addr_t tdg_shared_mask(void);
 extern int tdx_hcall_gpa_intent(phys_addr_t gpa, int numpages,
 				enum tdx_map_type map_type);
 
+int tdx_mcall_tdreport(u64 data, u64 reportdata);
+
 /*
  * To support I/O port access in decompressor or early kernel init
  * code, since #VE exception handler cannot be used, use paravirt
diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
index c71049cd2255..5eed2e660546 100644
--- a/arch/x86/kernel/tdx.c
+++ b/arch/x86/kernel/tdx.c
@@ -22,6 +22,7 @@
 /* TDX Module call Leaf IDs */
 #define TDINFO				1
 #define TDGETVEINFO			3
+#define TDREPORT			4
 #define TDACCEPTPAGE			6
 
 /* TDX hypercall Leaf IDs */
@@ -30,6 +31,9 @@
 /* TDX Module call error codes */
 #define TDX_PAGE_ALREADY_ACCEPTED	0x00000b0a00000000
 #define TDCALL_RETURN_CODE_MASK		0xFFFFFFFF00000000
+#define TDCALL_OPERAND_BUSY		0x8000020000000000
+#define TDCALL_INVALID_OPERAND		0x8000000000000000
+#define TDCALL_SUCCESS			0x0
 #define TDCALL_RETURN_CODE(a)		((a) & TDCALL_RETURN_CODE_MASK)
 
 #define VE_IS_IO_OUT(exit_qual)		(((exit_qual) & 8) ? 0 : 1)
@@ -140,6 +144,35 @@ bool tdg_debug_enabled(void)
 	return td_info.attributes & BIT(0);
 }
 
+/*
+ * tdx_mcall_tdreport() - Generate TDREPORT_STRUCT using TDCALL.
+ *
+ * @data        : Physical address of 1024B aligned data to store
+ *                TDREPORT_STRUCT.
+ * @reportdata  : Physical address of 64B aligned report data
+ *
+ * return 0 on success or failure error number.
+ */
+int tdx_mcall_tdreport(u64 data, u64 reportdata)
+{
+	u64 ret;
+
+	if (!data || !reportdata || !prot_guest_has(PATTR_GUEST_TDX))
+		return -EINVAL;
+
+	ret = __trace_tdx_module_call(TDREPORT, data, reportdata, 0, 0, NULL);
+
+	if (ret == TDCALL_SUCCESS)
+		return 0;
+	else if (TDCALL_RETURN_CODE(ret) == TDCALL_INVALID_OPERAND)
+		return -EINVAL;
+	else if (TDCALL_RETURN_CODE(ret) == TDCALL_OPERAND_BUSY)
+		return -EBUSY;
+
+	return -EIO;
+}
+EXPORT_SYMBOL_GPL(tdx_mcall_tdreport);
+
 static void tdg_get_info(void)
 {
 	u64 ret;
-- 
2.25.1